From 87b118a4e74b5d4985df80d74227fbf0701cb31d Mon Sep 17 00:00:00 2001
From: Jaime Oliveira <jaime.oliveira@uphold.com>
Date: Tue, 9 Jun 2026 11:55:37 +0100
Subject: [PATCH] feat(snowflake): use maximum VARCHAR length (128 MB) for
 string columns

---
 flow/model/qvalue/kind.go |  2 +-
 flow/shared/types/kind.go | 11 +++++++++--
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/flow/model/qvalue/kind.go b/flow/model/qvalue/kind.go
index 001eb9a6d..e613d46ac 100644
--- a/flow/model/qvalue/kind.go
+++ b/flow/model/qvalue/kind.go
@@ -71,7 +71,7 @@ func ToDWHColumnType(
 		} else if val, ok := types.QValueKindToSnowflakeTypeMap[kind]; ok {
 			colType = val
 		} else {
-			colType = "STRING"
+			colType = types.SnowflakeMaxVarchar
 		}
 		if nullableEnabled && !column.Nullable {
 			colType += " NOT NULL"
diff --git a/flow/shared/types/kind.go b/flow/shared/types/kind.go
index 76a184dad..6e5992d0d 100644
--- a/flow/shared/types/kind.go
+++ b/flow/shared/types/kind.go
@@ -69,6 +69,13 @@ func (kind QValueKind) IsArray() bool {
 	return strings.HasPrefix(string(kind), "array_")
 }
 
+// SnowflakeMaxVarchar is the maximum VARCHAR length Snowflake allows (128 MB).
+// A bare STRING/VARCHAR declaration defaults to 16 MB, so we specify the max
+// explicitly to avoid silently capping string columns. Snowflake bills storage
+// based on actual data stored and documents no performance difference between
+// max-length and shorter VARCHAR declarations.
+const SnowflakeMaxVarchar = "VARCHAR(134217728)"
+
 var QValueKindToSnowflakeTypeMap = map[QValueKind]string{
 	QValueKindBoolean:     "BOOLEAN",
 	QValueKindInt8:        "INTEGER",
@@ -82,7 +89,7 @@ var QValueKindToSnowflakeTypeMap = map[QValueKind]string{
 	QValueKindFloat32:     "FLOAT",
 	QValueKindFloat64:     "FLOAT",
 	QValueKindQChar:       "CHAR",
-	QValueKindString:      "STRING",
+	QValueKindString:      SnowflakeMaxVarchar,
 	QValueKindEnum:        "STRING",
 	QValueKindUint16Enum:  "INTEGER",
 	QValueKindJSON:        "VARIANT",
@@ -95,7 +102,7 @@ var QValueKindToSnowflakeTypeMap = map[QValueKind]string{
 	QValueKindDate:        "DATE",
 	QValueKindBytes:       "BINARY",
 	QValueKindUUID:        "STRING",
-	QValueKindInvalid:     "STRING",
+	QValueKindInvalid:     SnowflakeMaxVarchar,
 	QValueKindHStore:      "VARIANT",
 	QValueKindGeography:   "GEOGRAPHY",
 	QValueKindGeometry:    "GEOMETRY",